Our long range goal is to create an accurate method of vocal fold biopsy that does not result in clinically significant injury and voice dysfunction. The hypotheses this application is based on are: 1) that fine needle aspiration (FNA) of the vocal folds can be performed safely and will not result in clinically significant injury; 2) that FNA will provide enough cells for gene expression studies; and 3) that gene expression analysis will provide useful diagnostic and prognostic information. Essentially the application envisions the eventual use of a 25, 27, or 30 gauge needle for FNA of the diseased larynx (benign lesions, posterior glottis, areas of inflammation) in an outpatient or clinic setting. The FNA will provide cells for diagnosis, prognosis, or to assess response to treatment. As this is a feasibility application, this application focuses on the second hypothesis, that FNA will provide enough cells for gene expression studies. Additionally, although not the major focus of this application, some preliminary data will be gathered to address the third hypothesis. Aims of this application are: 1) determine the smallest number of cells necessary to achieve similar microarray results to a more traditional larger number of cells; 2) using an aspiration technique common for FNA of tissue, identify the smallest diameter needle that allows the harvesting of the required number of cells found in aim one; and 3) compare the gene expression profile obtained through FNA with the profile obtained from conventional biopsy, for normal laryngeal tissue and laryngeal pathologies. Use of linear amplification techniques for RNA from a small number of cells, microarray analysis comparisons between FNA samples and conventional biopsies, and obtaining vocal fold samples from organ donors make this application unique and possible. If this research is successful, the ability to perform and follow gene expression profiles during diagnosis and treatment will allow researchers to identify genes and pathways that: 1) help us understand the mechanism of the disorder; 2) locate areas that are promising for intervention and treatment; and 3) create biochips (a panel of genes) that are useful for diagnosis or prognosis.